1. Field of the Invention
This invention relates to a thin-film magnetic head.
2. Background Art
Increases in data recording capacity, faster access speeds and the like have been accompanied by rising demand for a thin-film head that has a higher permeability than the ferrite head and is able to maintain a high electromagnetic conversion efficiency even at high transfer rates. Thin-film magnetic heads require various ceramic substrate materials as sliders, and as the material for sliders there are used SiC, ZrO.sub.2, Al.sub.2 O.sub.3, Al.sub.2 O.sub.3 -TiC and the like.
For obtaining a thin-film head slider with stable flying characteristics and good running durability it is necessary to polish the medium-facing surface which constitutes the air bearing surface. As disclosed for example in Japanese Patent Public Disclosure Nos. Sho 60-185272, Sho 63-70918, Hei 2-199614, Hei 2-212057, Hei 2-301014 and the like, at the time of polishing the air bearing surfaces of the slider there is used a polishing film or a polishing tape.
On the other hand, from the point of improving running durability, it is preferable to bevel the edges (ridge portion) at the entire perimeter of the air bearing surfaces. This beveling is ordinarily conducted simultaneously with the polishing of the air bearing surface. Therefore, the size of the bevel differs variously with the surface polishing conditions. However, the aforesaid publications take no notice of, and are totally silent regarding, the dimensional precision of the beveled surfaces (edge surfaces) of the edges.
It has been found that when the air bearing surface(s), e.g. rail surfaces, are polished using a polishing film, since, under ordinary conditions, the amount of beveling conducted at the same time is slight, large variation in bevel size arises between different edge portions. The conventional slider having this variation in bevel size has not been satisfactory in the point of flying stability. More specifically, it has been found that flying instability is produced at CSS (Contact.multidot.Start.multidot.Stop), with increased roll angle variation in the flying attitude. It has further been found that it becomes impossible to secure flying characteristics when the degree of floating is increased.
The main object of this invention is to provide a thin-film magnetic head exhibiting stable flying characteristics, this being achieved by conducting the small amount of beveling conducted simultaneously with surface polishing with high precision.